A man who used Facebook to post a curse directed at a northern Nigerian governor has been arrested and jailed, police said today, a chilling warning about freedom of speech ahead of the oil-rich nation's coming elections.

Officers arrested Moukhtar Ibrahim Aminu in Jigawa state in late January for being a "public nuisance," police spokesman Abdul Jinjiri said.

Police held Aminu in jail for several days before bringing him to a local court, where he faced defamation charges. A judge sent him to jail pending trial.

Jinjiri said Aminu's crime stemmed from a comment he posted Jan 18 to the social networking website. Writing in the local Hausa language, Aminu asked that divine punishment be levelled against Jigawa state Gov Sule Lamido, a politician who helped form the ruling People's Democratic Party when Nigeria became a democracy more than a decade ago.

"Allah curse Sule Lamido and all his useless friends," the posting reads. "Allah make Sule Lamido and his friend useless."

Such curses can carry tremendous importance in Nigeria, a nation where animist beliefs mix with Christianity and Islam.

Some believe the curses can damage them for life, while others take them as an insult.

Nigerian law provides for freedom of speech in Africa's most populous nation. A 1983 court decision clearly shows that politicians and others cannot demand the arrest of individuals who slander, libel or defame them, said lawyer and civil rights activist Femi Falana.

Still, Aminu was arrested, apparently at the request of the governor or someone in state government upset by the statement.

"In Nigeria, a lot of illegalities are committed by the government," Falana said.